U.S. patent application number 13/261391 was filed with the patent office on 2013-05-02 for orthopedic device and method.
The applicant listed for this patent is Gamal Baroud, Stephan Becker, Denis Imbeault. Invention is credited to Gamal Baroud, Stephan Becker, Denis Imbeault.
Application Number | 20130110120 13/261391 |
Document ID | / |
Family ID | 44306345 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130110120 |
Kind Code |
A1 |
Baroud; Gamal ; et
al. |
May 2, 2013 |
ORTHOPEDIC DEVICE AND METHOD
Abstract
An orthopedic kit includes a hollow cannula having a distal end
including spiral thread for engaging a bone, an elongated probe
extending through the hollow cannula, and a metering device for
moving the probe such that a distal end of the probe is moved away
from a proximal end of the hollow cannula to into the bone to form
a channel in the bone whereby the metering device measures a force
applied by the distal end of the probe and thus the mechanical
strengh of the bone. A cement injector also forms part of the kit
which passes though the hollow canula beyond the distal end of the
cannula into the channel to inject cement into the surrounding bone
structure. A pedicle screw may also form part of the kit to be
placed in the channel before the cement is cured.
Inventors: |
Baroud; Gamal; (Canton
Hatley, CA) ; Becker; Stephan; (Vienna, AT) ;
Imbeault; Denis; (Sherbrooke, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baroud; Gamal
Becker; Stephan
Imbeault; Denis |
Canton Hatley
Vienna
Sherbrooke |
|
CA
AT
CA |
|
|
Family ID: |
44306345 |
Appl. No.: |
13/261391 |
Filed: |
January 20, 2011 |
PCT Filed: |
January 20, 2011 |
PCT NO: |
PCT/CA2011/000073 |
371 Date: |
August 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61296761 |
Jan 20, 2010 |
|
|
|
Current U.S.
Class: |
606/102 |
Current CPC
Class: |
A61B 17/3472 20130101;
A61B 2017/349 20130101; A61B 2017/0023 20130101; A61B 5/4504
20130101; A61B 17/3476 20130101; A61B 2090/065 20160201; A61B
2090/064 20160201; A61B 17/7001 20130101; A61B 17/8811 20130101;
A61B 2017/00398 20130101; A61B 17/864 20130101; A61B 17/1668
20130101; A61B 17/746 20130101; A61B 17/56 20130101; A61B 17/1671
20130101 |
Class at
Publication: |
606/102 |
International
Class: |
A61B 17/56 20060101
A61B017/56 |
Claims
1. An orthopedic kit for determining the mechanical strength of
bone comprising: a hollow cannula including an engagement member,
at least at a distal end thereof, for engaging a bone; an elongated
probe to be passed through the hollow cannula and having a length
sufficient to extend beyond the distal end of the cannula; a motor
device mounted in a housing attachable to the cannula with the
motor device connectable to the probe to drive the probe such that
a distal end of the probe is moved away from the distal end of the
hollow cannula to extend into the bone; and a metering device for
measuring a force applied by the probe to the bone.
2. The orthopedic kit as defined in claim 1 wherein the engagement
member is in the form of spiral threads on the surface of the
cannula.
3. The orthopedic kit as defined in claim 1, or 2 wherein the
metering device is mounted in said housing and is connectable to
the probe.
4. The orthopedic kit as defined in claim 1, 2 or 3 wherein the
metering device is a load cell.
5. The orthopedic kit as defined in any one of claims 1 to 4
further comprising a hollow cement delivery tube sized to extend
within the hollow cannula and having a length such that a portion
can extend beyond the distal end of the cannula.
6. The orthopedic kit as defined in claim 5 wherein the cement
delivery tube has a wall section that includes a plurality of
output ports defined in the portion that can extend beyond the
distal end of the cannula.
7. The orthopedic kit as defined in any one of claims 1 to 5
wherein the probe is hollow.
8. A method of measuring the mechanical strength of a bone,
comprising: engaging a distal end of a hollow cannula with the
bone; inserting an elongated probe into the hollow cannula;
advancing the elongated probe into the hollow cannula until the
elongated probe penetrates the bone; and while penetrating the bone
with the elongated probe, measuring a force applied by the
elongated probe on the bone as an indication of the mechanical
strength thereof.
9. The method as defined in claim 8 wherein the probe is advanced
by a drive motor in a housing anchored to the cannula at a proximal
end of the cannula.
10. The method of claim 8 or 9 wherein the force is measured by a
load cell in the housing and communicating with the probe.
11. The method as defined in claim 9 or 10 wherein the indication
of the mechanical strength of the bone is displayed on a display
that is part of the housing.
12. The method as defined in any one of claims 8 to 11 wherein the
cannula engages the bone in order to anchor the cannula to the bone
and to resist to the reactive forces of the probe being driven in
the bone.
13. A method of consolidating a bone, comprising: engaging a distal
end of a hollow cannula with the bone; inserting an indenter into
the hollow cannula and penetrating the bone with the indenter
beyond the distal end of the hollow cannula; removing the indenter
from the hollow cannula, thus leaving a channel defined in the
bone; engaging a screw into the channel; and retaining the screw
within the channel with bone cement.
14. The method of claim 13, wherein a force applied by the indenter
while penetrating the bone therewith is measured to provide an
indication of strength of the bone.
15. The method of claim 13 or 14, wherein prior to engaging the
screw in the channel, a cement delivery tube is inserted through
the hollow cannula into the channel and cement is then injected in
the bone surrounding the channel.
16. The method of claim 13 or 14, wherein the screw is a hollow
screw, and retaining the screw within the channel with bone cement
includes, after engaging the screw into the channel, injecting bone
cement into the bone through the hollow screw and out of lateral
ports defined along at least a majority of a length of the hollow
screw.
17. The method as defined in any one of claims 13 to 16 wherein
prior to the step on inserting the screw into the channel formed in
the bone, the hollow catheter is removed.
18. A bone screw comprising a head connectable to a cement delivery
device, and a hollow stem extending from the head and in fluid
communication therewith, the hollow stem being defined by a tubular
wall including threads on an exterior surface thereof, the tubular
wall including lateral ports defined there through along at least a
majority of a length of the hollow stem.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to orthopedics and procedures
such as vertebroplasty and arthroplasty. More particularly, a
minimally invasive device is provided for measuring the bone
quality as well as to improve the fixing of pedicle screws.
BACKGROUND ART
[0002] With an aging population it is important to improve the
screening of osteoporosis. Osteoporosis is a degenerative skeletal
disease that is characterized by reduced bone strength and exposes
patients to a greater risk of fracture most commonly at the spine,
wrist or hip. There are over three hundred million women/men taking
drugs and medication for osteoporosis. The conventional method of
measuring the quality of bone is to indirectly measure bone
density. Physicians do not have an objective method of measuring
the bone quality prior to, or during a procedure. Bone quality is
being mainly measured through imaging techniques and these
measurements are related to the density of the bone. The density of
the bone is indicative of the mechanical strength thereof, but not
always. There are some cases that show a dense bone that is
otherwise mechanically weak.
[0003] Surgeons often rely on a DXA scan of the patient. However,
in practice more than 50% of the procedures are conducted without
bone scans. For the remainder of the procedures physicians must
rely on their own experience making decisions based on subjective
data.
[0004] It has also been found that when repairing damaged bones
with screws, physicians will perform a vertebroplasty in order to
ensure that a pedicle screw will be properly fixed. But such a
procedure is excessive. As a result there are available canulated
pedicle screws to allow physicians to submit cement through the
screws once the screws have been placed in the pedicle. This
canulated screw includes a central bore with side fenestrations to
allow the cement to be distributed around the threads of the screw.
However it has been found that such techniques lead to significant
leakage while not providing sufficient cement to anchor the pedicle
screw.
[0005] Accordingly, improvements are desirable.
SUMMARY
[0006] It is therefore an aim of the present invention to provide
an improved orthopedic device and related methods.
[0007] Therefore, in accordance with the present invention, there
is provided an orthopedic device comprising a hollow cannula having
a distal end including an engagement member for engaging a bone, an
elongated probe extending through the hollow cannula, and a
metering device moving the probe such that a distal end of the
probe is moved away from a proximal end of the hollow cannula to
extend beyond the distal end of the hollow cannula, the metering
device measuring a force applied by the distal end of the
probe.
[0008] Also in accordance with the present invention, there is
provided a method of measuring a strength of a bone, comprising
engaging a distal end of a hollow cannula with the bone, inserting
an elongated probe into the hollow cannula, advancing the elongated
probe into the hollow cannula until the elongated probe penetrates
the bone, and while penetrating the bone with the elongated probe,
measuring a force applied by the elongated probe on the bone as an
indication of the strength thereof.
[0009] Also in accordance with the present invention, there is
provided a method of consolidating a bone, comprising engaging a
distal end of a hollow cannula with the bone, inserting an indenter
into the hollow cannula and penetrating the bone with the indenter
beyond the hollow cannula, removing the indenter from the hollow
cannula, leaving a channel defined in the bone, engaging a screw
into the channel, and retaining the screw within the channel with
bone cement.
[0010] Further in accordance with the present invention, there is
provided a bone screw comprising a head connectable to a cement
delivery device, and a hollow stem extending from the head and in
fluid communication therewith, the hollow stem being defined by a
tubular wall including threads on an exterior surface thereof, the
tubular wall including lateral ports defined therethrough along at
least a majority of a length of the hollow stem.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Reference will now be made to the accompanying drawings,
showing by way of illustration a particular embodiment of the
present invention and in which:
[0012] FIG. 1 is a perspective view of a typical vertebra;
[0013] FIG. 2 is a schematic lateral view of a spinal segment
showing a fractured vertebra;
[0014] FIG. 3 is a top view of a threaded cannula being placed in a
typical vertebra shown in horizontal crossection;
[0015] FIG. 4 is a schematic top view a handheld metering device
mounted to the indenter shown advanced in the vertebra;
[0016] FIGS. 5a and 5b are side views of the detail of a cement
injector;
[0017] FIG. 6 is a view showing the cement injector inserted into
the channel in the vertebra by means of the cannula and showing
cement seeping out of the distal end of the cannula;
[0018] FIG. 7a is a view of the vertebra with the cannula removed
and the pedicle screw being inserted into the channel formed in the
bone;
[0019] FIG. 7b is a view similar to FIG. 7a but showing the pedicle
screw anchored in the vertebra;
[0020] FIG. 8 is a fragmentary view of a pedicle screw in
accordance with another embodiment;
[0021] FIG. 9 is a schematic lateral view showing two vertebrae
fixed by pedicle screws and a bridge rod;
[0022] FIG. 10 is a lateral fragmentary schematic view showing a
channel, in the neck of the femoral bone, formed by the threaded
cannula and an indenter;
[0023] FIGS. 11a and 11b are lateral fragmentary schematic views
showing the details of the invention of FIG. 10 with the cement
injector in different operative positions;
[0024] FIG. 12 is a lateral fragmentary schematic view showing the
neck of a femoral bone using a dynamic hip screw in an attempt to
repair an intertrochanteric fracture with the use of cement to
anchor the dynamic hip screw.
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
[0025] Referring now to FIGS. 1 a vertebra 10 is illustrated having
a vertebral body 12 and a pedicle 14. In FIG. 2 a fractured
vertebra 10b is illustrated within a spinal segment consisting of
vertebrae 10a, 10b and 10c with vertebra 10b shown damaged. The
medical condition shown in FIGS. 2 may be corrected by using a
spinal fixation as will be described.
[0026] The following is a description of one embodiment of the
present invention as it applies to the spine. It is understood that
the device described in the present embodiment can be utilized to
repair other bone structures in the body as will be described
further below, for instance in pelvis or in the hip.
[0027] FIG. 3 illustrates a cannula 28 including a hollow stem 30
having an tapping threads 32 on its distal end for engaging the
bone. The proximal end of the cannula 28 includes a handle 34 and a
luer adapter 36. The cannula 28 is shown being inserted into the
pedicle 14 of a typical vertebra 10 to be repaired. The cannula 28
may be provided with a stylet (not shown) to ease the piercing of
soft tissues and bone.
[0028] FIG. 4 shows the use of a probe or indenter 40 having a
distal end 41 and a proximal end 42. The indenter 40 is a rod that
can pass through the bore formed in the stem 30 of the cannula 28.
The purpose of the indenter 40 is to allow an evaluation of the
quality of the bone. For instance, by applying a linear force on
the indenter 40 into the vertebral body the strength of the bone
can be measured by measuring the force required to advance the
indenter 40 in the bone structure of the vertebral body 12. Also
shown is a metering device 44 includes a motor (not shown) which
provides the force required to advance the indenter 40 into the
bone structure. A load cell (not shown) provides the data
representing the quality of the bone and the data is displayed on
the display 46. The metering device 44 includes a handle 48, and a
coupling device 50 adapted to be connected to the indenter 40.
Attachment devices 52 (not shown) maybe provided to connect the
metering device 44 to the luer 36 on the cannula 28.
[0029] The load cell measures the force as the indenter 40 advances
into the vertebra 10 by measuring the reaction force directly on
the indenter 40. Alternatively the force may be measured from the
current required to run the motor at a constant speed to advance
the indentor 40 at a constand velocity over a predetermined
distance. In one embodiment, the distance to be traveled is from 3
to 5 cm while the speed was determined to be 2.5 cm per second. The
indenter 40 and metering device 44 thus provide an instant and
objective measurement of the bone resistance to the compressive
force applied by the indenter 40, thus allowing a direct measure of
the hardness and strength of the bone. Since the cannula 28 is
anchored to the bone by means of the threads 32 and the metering
device 44 is fixedly coupled to the cannula 28, the device provides
the necessary support for the linear progress of the indenter 40 by
resisting the reaction force thereon.
[0030] In a particular embodiment, at least the indenter 40 is
disposable. A solid embodiment of the indenter 40 is shown.
Alternately the indenter 40 may be hollow. If the stem of the
indenter 40 is hollow it can be used to collect a core sample of
the bone for use in a biopsy examination.
[0031] Advantageously, the bone strength measurement can be done
prior to surgery. The advantage of the device is also that it can
be used in the examination room for mass screening and follow up on
therapeutic treatment. These measurements can be done under local
anesthesia and in outpatient clinics for screening of osteoporotic
patients.
[0032] The cannula 28 and indenter 40 can also be used to prepare
for the insertion of a bone screw. Once the indenter 40 has been
inserted into the body 12 of the vertebra 10 and the quality of the
bone structure has been measured, the indenter 40 is withdrawn from
the cannula, leaving behind a channel 54 (see FIG. 7a) in the
vertebral body 12.
[0033] FIG. 5a illustrates a cement delivery tube 56 including a
hollow stem 57 and a luer adapter 58 at its proximal end. The
diameter of the stem 57 is such that it can be easily inserted into
the hollow stem 30 of the cannula 28. FIG. 5b shows an enlarged
view of the stem 57 of the cement delivery tube 56 with a
fenestration zone 62 made up of a pattern of ports 62a. The ports
62a are consistently distributed throughout the fenestration zone
62. to allow a uniform dispersion of the cement when it is forced
through the cement delivery tube 56. In the embodiment shown, the
distal end 60 of the cement delivery tube 56 is blocked. The inner
diameter of the cement delivery tube 56 should be sufficiently
large as to form a path of least resistance for the cement so that
the cement will fill up the tube 56 before leaking through the
ports 62a. Once the tube 56 is filled with cement, the pressure is
built up within the delivery tube 56 and then the cement will flow
out of the tube 56 around the fenestration zone 62 in a uniform
manner. The length of the fenestration zone 62 can be varied to
thus control the pressure drop. Furthermore the shape, diameter,
and number of ports 62a in the fenestration zone 62 can be varied
in order to control the cement dispersion pattern.
[0034] As can be seen in FIG. 6, the cement delivery tube 56 is
inserted into the vertebral body 12 through the cannula 28. The
distal end 60 of the cement delivery tube 56 extends beyond the
distal end of the cannula 28 into the channel 54 formed in the bone
structure of the vertebral body 12 by the indenter. The
fenestration zone 62 extends within the channel 54. The luer
adapter 58 of the cement delivery tube 56 is connected to a cement
delivery device (not shown). The delivery tube 56 may be primed
with cement prior to being inserted into the vertebral body 12, or
may be simply inserted through the cannula 28 before cement is fed
thereinto. FIG. 6 shows, schematically, the dispersion pattern of
the cement after it has been injected through the cement delivery
tube 56. The cement delivery tube 56 could be flexible with memory
such that it can be curved to extend in a lateral direction once it
has extended beyond the distal end of the cannula 28.
[0035] Once the cement has been injected and is curing, but not yet
set, the next step involves removing the cannula 28 from the
vertebra 10 and inserting a pedicle screw 20 into the channel 54 as
shown in FIGS. 7a and 7b. The stem 21 of the pedicle screw 20 is
slightly larger than the channel 54 so that the tapping threads 26
of the pedicle screw positively engage the bone structure as well
as the cement C dispersed in the cavity formed in the vertebral
body 12. The pedicle screw 20 must be inserted into the channel 54
prior to the cement C being completely cured, and the cement will
set on the threads of the screw 20 in order to anchor it. The
procedure including the use of the cannula 28 and the cement
delivery tube 56 provides a prepared site for receiving the pedicle
screw 20.
[0036] FIG. 8 shows another embodiment of the pedicle screw. In
this embodiment, the pedicle screw 161 includes a stem 163 which is
hollow. The pedicle screw 161 also includes a head 164 connectable
to a cement delivery device (not shown) and spirals threads 166 on
the exterior surface of the hollow stem 163. Furthermore the hollow
stem 163 includes a large number of lateral ports 168 disposed
between the threads 166 and providing a fenestration zone 169
extending along a majority of the length of the pedicle screw 161,
and in the embodiment shown, extending along the entire length of
the screw 161. As can be seen, the pedicle screw 161 can be used as
an alternative to the cement delivery tube 56. The distal end 165
of pedicle screw is closed. Thus, as the cement is forced, under
pressure, into the hollow stem 163 of the screw 161, it will first
fill the hollow stem 163 whereby the pressure will increase until
the cement will start to flow uniformally through the lateral ports
168.
[0037] In this embodiment, the cannula 28 is removed once the bone
quality diagnostic procedure with the indenter 40 is terminated.
The channel 54 left by the cannula 28 and the indenter 40 serves to
receive the pedicle screw 161. Once the pedicle screw 161 is in
place within the channel 54, cement can be delivered through the
hollow stem 163.
[0038] FIG. 9 shows a typical spinal fixation 18 but using pedical
screws as described in the present specification. The fixation 18
includes pedicle screws 20 made up of a screw stem 21, head 22 and
spirals threads 26 on the stem 21. A bridge rod 24 is fixedly
connected to the pedicle screw heads 22 in order to provide a
proper stabilization structure between two healthy vertebra bodies
10a and 10c. Thus the fractured vertebra is protected against
motion occurring at the disc or vertebra 10b.
[0039] In another application of the present invention, there is
shown in FIG. 10 a typical hip 70. The hip 70 includes a femoral
bone 72 having a femoral head 74 and a femoral neck 76. The femoral
head 74 fits into the pelvis 78 as is well known. A fracture at the
femoral neck 76 and an intertrochanteric fracture are shown.
[0040] Similarly to the previously described application, the
cannula 28 is inserted into the femoral bone 72 coaxial with the
femoral neck 76, as shown in FIG. 10. The threads 32 of the cannula
28 engage the bone as it is being inserted. The indenter 40 is
inserted through the hollow stem 30 of the cannula 28 and is forced
under pressure into the bone structure of the femoral neck 76 and
into the head 74 for the purposes of measuring the quality of the
bone structure through the use of the metering device 44.
[0041] The indenter 40 once removed from the cannula 28 leaves a
channel 80 in the femoral neck 76 and head 74. As shown in FIG.
11a, the cement delivery tube 56, is then inserted through the
hollow stem 30 of the cannula 28 into the channel 80. As previously
described cement is then fed under pressure into the cement
delivery tube 56, and cement is expelled uniformly around the
fenestration zone 62. FIG. 11b shows a different application of the
cement delivery. In this embodiment the fenestrations zone 62 could
be located more toward the middle of the tube 56 or at the distal
end. The cement can thus de disposed as shown.
[0042] The location of the cement C in different locations such as
in the femoral head 74 or in the femoral neck 76. As previously
described, the design of the fenestration zone 62, whether at the
distal end of the delivery tube 56 or in the middle of the delivery
tube 56, dictates the location of the cement C which flows through
the tubes 56, with relative ease under pressure to be dispersed
uniformly around the fenestration zone 62, wherever it is
located.
[0043] Different applications of screws 20 to repair fractures in
the femoral neck 76 or the femoral head 74 may be contemplated. For
instance in FIG. 12, a dynamic hip screw 20 is shown, which is
similar to the pedicle screw 20 previously described. In all
applications the threads on the pedicle screws are cemented as
previously described. Alternately, hollow screws 161 similar to
those previously described may be used, such that the cement may be
injected directly therethrough.
[0044] The embodiments of the invention described above are
intended to be exemplary. Those skilled in the art will therefore
appreciate that the foregoing description is illustrative only, and
that various alternate configurations and modifications can be
devised without departing from the spirit of the present invention.
Accordingly, the present invention is intended to embrace all such
alternate configurations, modifications and variances which fall
within the scope of the appended claims.
* * * * *